Whether with or without a needle, injection syringes are configured to apply pressure to injection solution to inject the injection solution. Some needleless syringes that carry out needleless injection use an explosive as a pressure source (see e.g. Patent Literature 1). The needleless syringe disclosed in Patent Literature 1 is provided with a primer (or detonator) and a pyrotechnic charge. The primer is struck by a firing hammer to explode, so that the thermal energy of the explosion is transferred to the pyrotechnic charge. Consequently, the pyrotechnic charge burns to apply pressure to the injection solution. As the pyrotechnic charge, a single powder based on nitrocellulose is used.
The energy of combustion of powder is used as a power source for pressurization in fields other than syringes also. For instance, Patent Literature 2 discloses a technology relating to an actuator that interrupts the flow of medium in a fluid channel by driving a control member through a membrane using the energy of combustion of powder. In this technology, an elastically deformable membrane set between a control member and a housing is deformed by the pressure generated by the combustion of powder, so that a cylinder part attached to the film deforms to drive the control member.